Optical mark recognition (OMR), also referred to as optical mark reading, is the process of capturing human-marked data from document forms such as surveys, tests, or other substrates bearing markings. One of the most familiar applications of optical mark recognition is the use of #2 pencil (HB in Europe) bubble optical answer sheets in multiple choice question examinations. Students mark their answers, or other personal information, by darkening circles marked on a pre-printed sheet. Afterwards the sheet is automatically graded by a scanning machine.
Many traditional OMR devices work with a dedicated scanner device that shines a beam of light onto the form paper. The contrasting reflectivity at predetermined positions on a page is then used to detect these marked areas because they reflect less light than the blank areas of the paper.
FIG. 1 shows an example of a test form 100 that may be used with OMR. The form 100 typically is a thin sheet of paper having various markings such areas 102, which can take on various colors such as red, blue, orange, green, black, or grey, and multiple choice answer receiving areas 106, each area having a label A, B, C, D, or E. The example form shown in FIG. 1 has 250 answer receiving answers formed as a matrix having 50 rows, with five answer receiving areas 106 per row. While taking a test, the test taker uses a writing instrument to make a mark, such as oval 104, in one of the desired answer receiving areas 106 corresponding to which answer (A, B, C, D, or E) the test taker believes is correct. Once completed, the form 100 is handed in to the test proctor and it is run through an OMR scanner, which reads the positions of the markings and compares them to a predetermined set of correct answers. In this manner, the test taker's test form 100 is graded.